Circuit breaker operating system



May 18, 1943 CLOSE x C C. THUMIM CIRCUIT BREAKER OPERATING SYSTEM FiledNov. 29, 1940 2 Sheets-Sheet l Figi Inventor: Carl Th umim,

H ls Attorw ey.

CIRCIT BREAKER OPERA'I-ING SYSTEM Filed Nov. 29; 1940 l.2 sheets-sheet 2AUTOMATIC REcLoslNG CLOSE Swnrcrl Inventor: Carl Th umm,

His Attorney.

Patented May 18, 1943 CIRCUIT BREAKER OPERATING SYSTEM Carl Thumim,Yeadon, Pa., assgnor to General Electric Company, a corporation of NewYork Application November 29, 1940, Serial No. 367,788

17 Claims.

My invention relates to circuit breaker operating systems, moreparticularly to pneumatic operating systems for effecting high speedautomatic reclosure of a circuit breaker, and has for its principalobject the provision of an improved circuit breaker operating andreclosing system of the aforesaid type that is rapid, positive andefficient, particularly with respect to the reclosing operation, thathas low input power rating, and that is applicable to large circuitbreakers requiring a considerable closing force.

A further object of my invention is the provision of an improvedpneumatic automatic circuit breaker reclosing system that is effectiveto apply the reclosing force in a positive manner and without delay at apredetermined intermediate lpoint in the breaker opening stroke, andthat is automatically preset for high speed reclosing.

Means have been provided for quickly reclos- 'f ing electric circuitbreakers in electric distribution systems Where continuity of service isa very important factor, one or more times after automatic opening inresponse to a fault. This is desirable in View of the fact that a verylarge percentage of faults, such as short circuits due to lightning, forexample, can be cleared by a single breaker operation. In synchronizedcircuits, however, the circuit reclosures must be made at very highspeed if the synchronous load is to be held on the line.

From the standpoint of service continuity, the ideal condition is thatthe breaker be reclosed instantly after the breaker has cleared thefault, preferably after a very short opening stroke. Accordingly, wherestandard opening and closing mechanisms are employed, reclcsure does notactually start until the full opening stroke has been completed, i. e.,an appreciable time after the fault current has been interrupted.

rI'he function of a circuit breaker is not only to open a circuit andclear faults, but also to maintain the circuit clear in the open circuitposition under adverse voltage conditions. That is, the length of strokeof the circuit breaker must be suiiicient not only to interrupt theheaviest currents for which the breaker is rated, but also to preventrestriking of the arc in case the line voltage is several times that ofnormal. As contrasted with this isolating function of the breaker. itshould be borne in mind that a well designed breaker can actually cleara fault within a few inches of opening stroke.

In accordance with the present invention, a fiuid motor, such las apiston and cylinder arranged for example for pneumatic operation, isconnected to a source of gas pressure, such as a storage tank forclosing a circuit breaker and for rapidly reclosing it after a trippingoperation with minimum expenditure of gas energy. To this end, means areprovided for initially presetting the uid motor with respect to thebreaker operating mechanism so that no time is lost in initiating thereclosing operation.

My invention will be more fully set forth in the following descriptionreferring to the accompanying drawings, and the features of noveltywhich characterize my invention will be pointed out with particularityin the claims annexed to and forming a part of this specification.

Referring to the drawings, Figure 1 is a partly diagrammatic layout of ahigh speed automatic circuit breaker operating and reclosing system inthe closed circuit position embodying the present invention, and Figure2 is a similar View showing the application of the invention to anotherform of operating mechanism.

rIhe pneumatic operating mechanism illustrated by way of example in Fig.1 comprises a fluid motor l of the piston and cylinder type, a source ofcompressed gas 2 for operating the motor and a circuit breaker operatingmember 3 that is operatively connected by a iiexible linkage 4 to thepiston 5 of the uid motor. The circuit breaker (not shown) can in thepresent instance conveniently be of the gas blast type by reason of thesource of compressed gas 2, although it will be apparent that anysuitable type can be used.

In the position shown, the circuit breaker operating member or rod 3 isheld by means hereinafter described in the closed circuit position, acompression spring 6 biasing the breaker and mechanism toward opencircuit position. The operating means interconnecting the breaker rod 3and the piston 5 may be of the chain linkage type as described andclaimed in Thumim Patent 2,112,054, granted March 22, 1938, forOperating mechanism.

The breaker rod 3, which is suitably guided for longitudinal reciprocalmovement at 1, is directly connected through the flexible chain linkagei to the piston rod 5. A spring 5" is also connected to the piston rodto bias it toward its upper or reset position. The piston rod 5 is heldin the depressed or closed circuit position :shown against the bias ofsprings 5" and 6 by a prop E that is pivotally mounted at and is biasedin a counter-clockwise direction by a spring 8" so as to ride over andengage a pin 9 secured to the piston rod 5'.

The chain linkage 4 is particularly adapted for applications requiringmovement of the circuit breaker operating rod at right angles to thedirection of the operating force and is held in operative position by acrank ID that is pivotally mounted at II and is provided with rollers I2and I3 at the extremities of the crank arms. The roller l2 serves as arolling guide for the chain linkage 4, and the roller I3 cooperates witha pivoted latch I4 that is in turn associated with a tripping solenoidI5. The latch I4 is spring biased at I6 in counter-clockwise directionso that it can reset beneath the roller I3 and the crank I is alsobiased counter-clockwise by a spring I'I for the purpose of stretchingthe chain 4 and returning the crank to a reset position with respect tothe latch I4 As shown, the crank I is held against rotation by the latchI4 so that the linkage 4 is under tension for holding the breaker rod 3in closed circuit position.

A more detailed description of the chain linkagemechanism is believed tobe unnecessary other than to point out that upon clockwise movement ofthe latch 'I4 in response to actuation of the tripping solenoid I5, thebreaker spring 6 causes rotation of the crank I0 clockwise, taking upslack in the chain 4 and thereby permitting opening movement of thebreaker rod. Upon initial clockwise rotation of the crank I0, the prop 8is also pushed away from the pin roller 9 by reason of a camming actionat I0' between the crank Ill and an extension I8 of the prop 8. Thepiston rod can now move to its upper position, taking with it the piston5, for producing more slack in the chain 4 so as to allow completeopening of the breaker and to permit resetting of the crank I0 underinfluence of its spring I1. The breaker is now open and the mechanismreset and in readiness for a closing operation.

It will be* noted that there is a lost-motionV connection between thepiston 5 and its operating rod 5'. This is for the purpose of presettingthe piston independently of the piston rod and breaker mechanism afterthe closing operation so that high speed reclosure can take placeunhampered by preliminary piston movement durs intermediate or partialstroke position as shown.

This position corresponds approximately to the beginning of thereclosing stroke.

To initiate the normal closing operation of this type mechanism, gasunder pressure is admitted to the piston cylinder I9 by a control valve2li for moving the piston 5 downward,

^ theV piston now being in operative engagement with the piston rodcollar 5a at the upper part of the cylinder. The crank I0, which is nowreset and inthe position shown, holds the chain linkage taut so that thebreaker rod 3 is moved by the 'piston against the bias of opening spring6 to the closed circuit position shown. When the piston reaches itslower limit of travel, the

prop 8 snaps over the pin roller 9 and holds the breaker in closedcircuit position independently of the uid motor I.

The normal tripping operation is as above described, that is,energization of the tripping solenoid I5 in response to a faultcondition in the circuit, for example, causes release of the latch I4and collapse of the chain linkage 4 so as to permit opening movement ofthe breaker.

It will be noted that the operating mechanism above described istrip-free during the closing operation of the breaker. That is, trippingof the latch I4 prior to complete closing of the breaker is eiective tocause immediate opening movement of the breaker notwithstanding the factthat the piston 5 is in driving relation to the piston rod 5', and hencethe mechanism.

The operating mechanism so far described performs the normal circuitclosing and opening operations wherein the breaker operating member ismoved throughout its full stroke for each operation. That is, when thebreaker opens fully, the mechanism carries the piston 5 upward to thebeginning of the stroke, and when the breaker is completely closed thepiston moves to the end of the stroke against the bias of resettingsprings 5d. However, immediately after closing of the breaker andshutting off of the closing force, the presetting means 5c-5d causereturn of the piston, independently of the mechanism and circuitbreaker, to the intermediate or preset position shown, f

In the case of high speed reclosing, it is essential that the breakerreclosing movement be initiated after but a fraction of the normalopening stroke as previously pointed out. To this end, the fluid motor Iis controlled by the valve 20 so that a fresh charge of compressed gasis admitted to the cylinder I9 after predetermined opening of thebreaker so that the piston 5 is immediately driven back through apartial stroke to its fully closed position. Since the cylinder workingspace is small as compared with the case of prior types of pistonmechanisms, a comparatively small charge of compressed gas under sourcepressure quickly raises the cylinder pressure to accomplish at vhighspeed the desired reclosing stroke.

The control means for accomplishing high speed reclosing comprise anauxiliary switch 2I arranged to control energization of the valveoperating solenoid 22, and means hereinafter described for controllingtripping of the chain linkage mechanism'at the latch I 4. The auxiliaryor reclosing switch 2i is arranged to be engaged by a cam or the like 3secured to the breaker rod 3 for closing the switch 2I when the breakerrod has moved a predetermined distance toward open circuit position.This distance corresponds to the length of stroke for clearing thefault. The switch 2! is connected so as to be in series with a manualreclosing control switch 23 that is mechanically connected to a trippingswitch 24.

. When the reclosing cycle is to be used, the switch 23 is put in theposition shown and upon opening movement of the breaker the energizingcircuit of the valve solenoid 22 is completed from the source of controlvoltage indicated at e through the reclosing control switch 23,automatic reclosing switch 2l, source-pressure control switch 25, and alimit or cuto switch 26 that is spring biased towards closed position.The switch 25 is for the purpose of rendering the system inoperative incase of failure ofthe gas source pressure at 2, and the switch 26automatically deenergizes the valve solenoid-when it is opened 26 alsodrops down to close the switch 26. When this takes place, the automaticreclosing switch at 2|1is closed, as in Fig. l, for energizing theclosing circuit of the Valve solenoid 22. Similar auxiliary switches andcontrol means having corresponding reference numbers are used and, sincethe functions are generally similar, further detailed description of themechanism and system is unnecessary and the operation will be clear Yfrom the following brief description: When the trip coil 36 is energizedby the fault relay FR,

the mechanism is tripped open. After predetermined opening movement, thevalve solenoid 22 is energized through the auxiliary switches 2|, 26 and25, and compressed gas is immediately admitted to the cylinder i9. Sincethe opening movement so far has simply taken up the lostmotion at f, thepiston is now in instant readiness to reclose the breaker by rotatingthe link 4|' counterclockwise. This reclosing operation is possiblesince 46 is still latched. Near the end of the piston closing stroke theauxiliary limit switch 26 is opened to deenergize the valve solenoid 22.

If now the fault persists even after reclosing, the trip-free coil I5,which is now in the tripping circuit by means of the pressure operatedtransfer relay TR, is energized to trip the latch itv thereby causingimmediate reopening of the breaker to the full open position. In thisposition the piston 5 is at the lower part of the cylinder, the pin 5enow being in abutting contact Awith the piston rod so that uponresetting of the latch 46, the mechanism is in readiness for a newclosing operation. With the pin 5e in its lower position the limitswitch 26 is again closed, thereby placing the control circuit inreadiness for the next closing operation when the manual switch at C isclosed.

It should be understood that my invention is not limited to specificdetails of construction and arrangement thereof herein illustrated, andthat changes and modifications may occur to one skilled in the artwithout departing from the spirit of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. An automatic reclosing circuit breaker system comprising a iiuidmotor operable through a working stroke to close the circuit breaker, asource of iiuid pressure for operating said motor, means for presettingsaid motor after a working stroke independently of said circuit breakerat an intermediate point in said stroke, a control valve for admittingsaid fluid to said motor, tripping means for said circuit breaker, andmeans operative in response to predetermined opening movement of saidcircuit breaker upon actuation ci said tripping means for opening saidvalve and causing reversal of movement of said motor from saidintermediate point to reclose said circuit breaker through a partialworking stroke prior to completion of the opening stroke thereof. i

2. An automatic reclosing circuit breaker system comprising a fluidmotor operable through a working stroke to move the circuit breaker toclosed circuit position, spring means arranged to be stressed by saidfluid motor for biasing said circuit breaker toward open circuitposition,

v means for presetting said motor after said working stroke at a pointcorresponding to a partial down in response to tripping, the slottedlink 26a. vinterconnecting the linkage and the limit switch workingstroke, said presetting loperation being eiiected independently of saidcircuit breaker, a source of fluid pressure for operating said motor, acontrol valve between said source and motor, tripping means forreleasing stored energy in said spring means for causing openingmovement of said circuit breaker, and means operable by and inaccordance with predetermined opening movement of said circuitbreakerfor causing opening of said valve and actuation of said iiuid motorthrough the remainder of said stroke to reclose said circuit breakerprior to completion of the opening stroke thereof.

3. An automatic reclosing circuit breaker system comprising an operatingpiston, means including a lost-motion connection interconnecting thecircuit breaker and said piston, tripping means for said circuitbreaker, a spring for biasing said circuit breaker toward open circuitposition, a source of iiuid pressure for operating said piston so as tocause closing movement of said circuit breaker against the bias of saidspring, means for presetting said pistonv independently of said circuitbreaker at an intere mediate point in its closing stroke through `saidlost-motion connection, a control valve between tion connectionoperatively relating said piston to said circuit breaker, said pistonarranged to preset to an intermediate position through said lost-motionconnection independently of said circuit breaker after the closingstroke, a spring arranged to bias said circuit breaker toward opencircuit position independently of said preset piston, a source of fluidpressure for driving said piston through a working stroke to causeclosing movement of said circuit breaker through said trip-freeconnection, a control valve between said source and piston, a latch forreleasing said spring for initiating opening movement of said circuitbreaker, reclosing means operable in response to predetermined openingmovement of said circuit breaker for opening said valve whereby saidpiston is instantly started from its preset position and the circuitbreaker is reclosed prior to completion of the opening stroke thereof,and means for releasing said trip-free connection for causing opening ofsaid circuit breaker in the event that said reclosing operation isconcurrent with a circuit fault.

5. An automatic reclosing circuit breaker system comprising a source ofgas pressure, a uid motor having a cylinder and piston, a control valvebetween said source and cylinder, means including a lost-motionconnection operatively connecting said piston and the circuit breakerarranged so that said piston is eiective to close said circuit breakerthrough a positive working stroke and said circuit breaker is free toopen initially a predetermined distance independently of said piston,spring means arranged to bias said circuit breaker toward open circuitposition, said tripping means for causing opening movementof saidcircuit breaker, and means for opening said valve upon opening of saidbreaker said predetermined distance and taking up of said ylost-'motionconnection for admitting gas under source pressure to the cylinder spaceat the working side of vsaid piston for reclosing sa circuit breakerprior to completion of the opening stroke thereof.

6. An automatic reclosing circuit breaker system comprising a source ofgas pressure, a iiuid motor having a cylinder and. piston, meansincluding a lost-motion connection operatively connecting said piston tothe circuit breaker, a valve for controlling admission of gas from saidsource to said cylinder to effect a working stroke of said piston forclosing said circuit breaker, said piston being independently movablethrough said lostmotion connection to preset at an intermediate point inits stroke after said breaker closing, fault responsive means forcausing opening of said circuit breaker to take up the lost-motion withsaid piston, and means operable in response to predetermined circuitopening movement of said breaker to cause opening of said valve foradmitting gas under source pressure directly to the cylinder workingspace whereby said piston is moved from its preset position through theremainder or" its working stroke and said circuit breaker is reclosedprior to completion of its opening stroke.

7 An automatic reclosing circuit breaker system comprising a source ofgas pressure, a fluid motor, means operatively connecting said motor tothe circuit breaker including trip-free means, a valve for controllingadmission of gas from said source to said motor to cause closing of saidcircuit breaker, means for holding said circuit breaker in closedcircuit position against an opening bias, fault responsive meanscoacting with said holding means for causing opening of said circuitbreaker, means operable upon predetermined circuit opening movement ofsaid breaker to cause opening of said valve for admitting gas from saidsource to the Working space of said motor whereby said circuit breakeris immediately reversed and reclosed prior to completion of its openingstroke, and pressure responsive means communicating with said motorworking space for placing said circuit breaker under control of saidtrip-free means during the aforesaid closing and reclosing operations.

8. An automatic reclosing circuit breaker system comprising a source ofgas pressure, a iiuid motor, means operatively relating said motor tothe circuit breaker including trip-free means, a valve for controllingadmission of gas from said source to said motor to cause closing of saidcircuit breaker, means for holding said circuit breaker in closedcircuit position independently of said motor against an opening bias,fault responsive means coacting with said holding means for causinginitial opening of said circuit breaker, means operable upon partialcircuit opening movement of said breaker for admitting gas from saidsource to said motor whereby said circuit breaker is immediatelyreversed after said partial movement and reclosed, and pressureresponsive means operable when said motor is supplied with gas pressurefor placing said circuit breaker under control of said trip-free meansduring the aforesaid reclosing operation.

9. An automatic reclosing circuit breaker system comprising a source ofgas pressure, a fluid motor having a piston arranged for reciprocalmovement, means operatively connecting the piston rod of said piston tothe circuit breaker, a lost-motion connection between said piston andsaid piston rod corresponding to a partial opening stroke, a valve forcontrolling admission of gas lfrom said source to said piston to causeclosing of said circuit breaker, means for holding said circuit breakerindependently of said piston in closed circuit position against anopening bias, means for presetting said piston at a point correspondingto said partial opening stroke, fault responsive means coacting withsaid holding means for causing initial opening of said circuit breakerindependently of said piston to take up said lostmotion, and meansoperable upon said partial circuit breaker opening movement to causeopening of said valve for admitting gas from said source to said pistonwhereby said circuit breaker is immediately reversed after said partialmovement and reclosed.

10. An automatic reclosing circuit breaker system comprising a source ofgas pressure, a fluid motor having a piston arranged for reciprocalmovement, means including a mechanical lostmotion connection operativelyconnecting said piston to the circuit breaker, a valve for controllingadmission of gas from said source to said piston to cause closing ofsaid circuit breaker, means for holding said circuit breaker in closedcircuit position independently of said piston against an opening bias,said piston thereby being permitted to preset through said lostmotionconnection to a partially open position, fault responsive means coactingwith said holding means for causing opening of said circuit breaker,said breaker after partial opening movement being in driving relation tosaid piston, and means operable upon said partial circuit breakeropening movement to cause opening of said valve vfor admitting gas fromsaid source to said piston fault condition when said circuit breaker isnormally closed, trip-free means for also tripping said circuit breakerwhen it is closed during a fault condition, and pressure-responsivemeans operable when pressure is applied to said uid motor fortransferring the tripping control from said first-named tripping meansto said trip-free means.

12. An automatic reclosing circuit breaker system comprising a fluidmotor operable through a working stroke to close the circuit breaker, asource of uid pressure for operating said motor, means for presettingsaid motor after a working stroke independently of said circuit breakerat an intermediate point in said stroke, control means for admittingsaid fluid to said motor, tripping means for said circuit breaker, meansoperative in responsive to predetermined opening movement o said circuitbreaker for admitting fluid to said motor and causing reversal ofmovement of said motor from said intermediate point to reclose saidcircuit breaker, and pressure responsive means connected to said motorfor controlling said tripping means.

13. An automatic reclosing circuit breaker system' comprising asource ofgas pressure, a fluid motor operable by said pressure, means operativelyrelating said motor to the circuit breaker for closing said circuitbreaker, means for tripping said circuit breaker in response to a faultcondition, trip-free means for also tripping said circuit breaker Whenitis closed duringa fault condition, and pressure-responsive meansassociatedwith said fluid motor for controlling the tripping of. saidfirst-named trippingmeans and said trip-free means. v

14. An automatic reclosing circuit breaker sys.,-V tem comprising anoperating piston, means including a trip-freeconnection and alost-motion connection operatively relating said piston to said circuitbreaker, said piston being biased to preset to an intermediate positionthrough said lostmotion connection independently of said circuit breakerafter the closing stroke, a source of fluid pressure for driving throughsaid trip-free connection said piston through a working stroke to causeclosing movement of said circuit breaker, a control valve between saidsource and piston,

means for initiating opening movement of said.

circuit breaker independently of said trip-free connection, reolosingmeans operable in response to predetermined opening movement of saidcircuit breaker for opening said valve to start said piston from itspreset position so that the circuit breaker is reclosed prior tocompletion of the opening stroke thereof, means for releasing saidtrip-free connection for causing opening of said circuit breaker in theevent that said reclosing operation is concurrent with a circuit fault,and means responsive to fluid pressure at said piston for controllingthe aforesaid trip-free connection.

- l15. An automatic reclosing circuit breaker sys-f tem comprising asource of gas pressure, a uid motor having a cylinder and piston, anoperating trip-free linkage interposed with respect to said piston andthe circuit breaker, a lost-motion connection between said piston andoperating linkage, a valve for controlling admission of gas from saidsource to said cylinder so as to produce a working stroke of said pistonfor closing said circuit breaker, said piston being biased forindependent movement through said lost-motion connection to preset at anintermediate point in said stroke after closing of said breaker, faultadmitting gas to the working space of said motorY responsive means forreleasing said .linkage and causing opening of said circuit breaker fortake' ing up the lost-motion with said piston, and means operable inresponse to'predetermined circuit opening movement of said breaker tocauseopening of said valve for admitting gas under pressure directly tothe cylinder Working space 'so that said piston is moved through afraction of itsk Working stroke and said circuit breaker is reclosedprior to completion of its opening stroke.

16. An automatic reclosing'circuit breaker system comprising a source ofgas pressure, a fluid motor, means operatively connecting said motor vtothe circuit breaker including trip-free means,

whereby said circuit breaker is immediately reversed and reclosed priorto completion of its.

opening stroke, and pressure responsive means communicating with saidmotor Working space for placing said circuit breaker under control of'said trip-free means during the aforesaid closing and reclosingoperations.

17. An automatic reclosing circuit breaker system comprising a source ofgas pressure, a uid motor having a piston arranged for reciprocalmovement, an operating linkage between the piston rod and the circuitbreaker, means including a mechanical lost-motion connection intercon- 1necting the piston rod and said linkage, a valve for controllingadmission of gas from said source.

to Vsaid piston to cause closing of said circuit breaker, said pistonwhen the breaker is closedl being biased to preset through saidlost-motion connection to a partially open position, fault responsivemeans for causing opening of said circuit breaker, said breaker afterpartial opening movement being in driving relation to said piston, andmeans operable in response to said partial circuit breaker openingmovement to cause opening of said valve for admitting gas from saidsource to-said piston so that said circuit breaker is immediatelyreversed and reclosed prior to completion of its opening stroke.

CARL THUMIM.

